1. Field of the Invention
This invention relates to power supplies and particularly to a low loss flyback type power supply for charging networks such as capacitive type pulse forming networks.
2. Description of the Prior Art
In power supplies designed for charging capacitive type loads such as a pulse forming network (PFN), it is common to use transistor switches and inductive energy storage to provide relatively efficient power transfer. Prior art circuits generally are either of a high dissipation type which utilize series resistance to limit the initial charging current or use flyback switching regulators in which transistors interrupt large currents in inductive circuits allowing the inductively stored energy to be transferred to the capacitive load. Generally several hundred to a few thousand cycles of the transistor switch are required for a single PFN charging and each time the transistor is turned off the voltage across the switching device rises to greater than the supply voltage prior to the current decreasing, thus producing relatively high instantaneous losses. A charging circuit that would eliminate the brief periods of high dissipation by performing all switching operations when substantially zero current is passing through the switch would be a substantial advantage to the art.